Pull it. It is IMO, a week link in the system. Instead of being a safety warning device it is a safety hazard (particularly older units). Mine drained the MC during a 1000 mi road trip, the sensor never illuminted. After tearing out the PWDA in a gravel parking lot and reconnecting the lines with some unions from the local auto parts store it has been great for the past two years.
1970 SIIA 88, Sold